Sunday, September 27, 2020

Waste Water Treatment using Graphene

Water pollution because of toxic organic contaminants such as dyes, pesticides, hydrocarbons, antibiotics, etc. becomes a serious problem in a global scale today. Various technologies are developed for the treatment of contaminated water such as chemical precipitation, ion-exchange, adsorption, membrane filtration, coagulation-flocculation, floatation, electrochemical methods, and advanced oxidation are used in recent years.

            Advanced oxidation processes in presence of nanomaterials gained wide attention for the remediation of contaminated water over the conventional methods because of its low cost, less time consuming and simple in process. In this process, development of efficient semiconductor based photocatalysts play a vital role. Among several nanomaterials, graphene based nanomaterials are important for the enhancement of photocatalytic activity of semiconductor nanostructures.

            Due to the unique properties of graphene it is used for remediation of contaminated water. The graphene based nanomaterials offer several advantages due to their large surface area and high electron content for the removal of organic species from waste water. Graphene oxide (GO) is used due to its high oxygen contents, which is responsible for the adsorption of metal ion in the GO sheets. The surfaces of the hydrophobic materials can be functionalized to target the specific contaminant via electrical and chemical interaction.

            A composite with GO and metal oxide have some useful features and used as effective adsorbent in the waste water treatment. GO functionalised magnetic nanomaterials are used for the rapid removal of tetracycline, oxytetracycline, dioxytetracline organic pollutants. Reduced graphene oxide (rGO)/iron oxide composite has been proved to be an excellent adsorber for the removal of 1-naphthylamine, 1-naphthol and naphthalene like compounds.

            From the various studies it is obvious that rGO-TiO2, single layer GO, TiO2-Graphene sponge have higher tetracycline and ciprofloxacin adsorption capacity than any other metal oxide based nanomaterials. GO-EDTA showed excellent Pd2+ adsorption capacity than any other adsorbant. Besides metal removal graphene based material is also used for the removal of organic pollutants by adsorption. In this way we can utilise the unique properties of graphene and graphene based nanomaterials to minimize environmental pollution and health hazards.

 References:

1.         S. S. Boxi, S. Paria. Visible light induced enhanced photocatalytic degradation of organic pollutants in aqueous media using Ag doped hollow TiO2 nanospheres. RSC Adv 2015; 5, 37657-37668.

2.         R. Levin, P. Epstein, T. Ford, W. Harrington, E. Olson, E. Reichard, US drinking water challenges in the 841 twenty-first century, Environmental Health Perspectives 2002, 110, 43-52.

3.         X. Qu, J. Brame, Q. Li, P.J.J. Alvarez, Nanotechnology for a Safe and Sustainable Water Supply: 846 Enabling Integrated Water Treatment and Reuse, Accounts of Chemical Research, 2012, 46, 834-843.


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